It is known that in electric household appliances of the aforesaid type, the tank either underneath the washing chamber (in a dishwasher) or containing the basket (in a washing machine) is intended to collect a predetermined level of water, which is only exceeded in case of malfunctioning. At least one pressure sensor (pressure switch), hydraulically connected to the top of the tank or sump itself by means of a flexible pipe, is used to detect the level of water in the tank, within which tank or sump the pressure of the air trapped therein varies according to the level of water in the tank and, thus, according to the amount of liquid present in such a collecting volume.
If the volume of liquid exceeds the predetermined level, however, part of the liquid may flow up along the flexible connecting pipe and reach the sensor, thus damaging it.
Therefore, as a safety measure, the sensor is not directly connected to the flexible pipe, but through a protected, fluidic connecting device which defines a siphon air trap therein, which is interposed between a first joining union to the flexible pipe and the sensor itself, immediately upstream of the sensor.
In the known protected, fluidic connecting devices, the siphon air trap consists of a branch of a U-shaped pipe which connects the first union to a second union of the device, which is in use connected to an inlet nipple of the sensor. Such a solution is however relatively costly, large in size and unsuitable for a fast fitting, in particular of automatic type.